title: Effects of background fluid on the efficiency of inactivating yeast with non-thermal atmospheric pressure plasma.
abstract: Non-thermal plasma at atmospheric pressure has been actively applied to sterilization. However, its efficiency for inactivating microorganisms often varies depending on microbial species and environments surrounding the microorganisms. We investigated the influence of environmental factors (surrounding media) on the efficiency of microbial inactivation by plasma using an eukaryotic model microbe, Saccharomyces cerevisiae, to elucidate the mechanisms for differential efficiency of sterilization by plasma. Yeast cells treated with plasma in water showed the most severe damage in viability and cell morphology as well as damage to membrane lipids, and genomic DNA. Cells in saline were less damaged compared to those in water, and those in YPD (Yeast extract, Peptone, Dextrose) were least impaired. HOG1 mitogen activated protein kinase was activated in cells exposed to plasma in water and saline. Inactivation of yeast cells in water and saline was due to the acidification of the solutions by plasma, but higher survival of yeast cells treated in saline may have resulted from the additional effect related to salt strength. Levels of hydroxyl radical (OH·) produced by plasma were the highest in water and the lowest in YPD. This may have resulted in differential inactivation of yeast cells in water, saline, and YPD by plasma. Taken together, our data suggest that the surrounding media (environment) can crucially affect the outcomes of yeast cell plasma treatment because plasma modulates vital properties of media, and the toxic nature of plasma can also be altered by the surrounding media.
authors.affiliation: Plasma Bioscience Research Center, Kwangwoon University, Seoul, Korea.
authors.forename: Young-Hyo
authors.initials: YH
authors.lastname: Ryu
authors.forename: Yong-Hee
authors.initials: YH
authors.lastname: Kim
authors.forename: Jin-Young
authors.initials: JY
authors.lastname: Lee
authors.forename: Gun-Bo
authors.initials: GB
authors.lastname: Shim
authors.forename: Han-Sup
authors.initials: HS
authors.lastname: Uhm
authors.forename: Gyungsoon
authors.initials: G
authors.lastname: Park
authors.forename: Eun Ha
authors.initials: EH
authors.lastname: Choi
mesh_terms: D000935:Antifungal Agents / Q000494:pharmacology*; D001128:Argon / Q000494:pharmacology*; D003470:Culture Media / Q000737:chemistry; D004271:DNA, Fungal / Q000235:genetics; D016681:Genome, Fungal; D042822:Genomic Instability; D006863:Hydrogen-Ion Concentration; D015227:Lipid Peroxidation; D050296:Microbial Viability; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D010766:Phosphorylation; D058626:Plasma Gases / Q000494:pharmacology*; D011499:Protein Processing, Post-Translational / Q000187:drug effects; D026361:Reactive Nitrogen Species / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000502:physiology*; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism; D012965:Sodium Chloride / Q000737:chemistry; D012996:Solutions; D013242:Sterilization / Q000379:methods*; D014867:Water / Q000737:chemistry
chemical_list: D000935:Antifungal Agents; D003470:Culture Media; D004271:DNA, Fungal; D058626:Plasma Gases; D026361:Reactive Nitrogen Species; D017382:Reactive Oxygen Species; D029701:Saccharomyces cerevisiae Proteins; D012996:Solutions; D014867:Water; D012965:Sodium Chloride; D001128:Argon; C088589:HOG1 protein, S cerevisiae; D020928:Mitogen-Activated Protein Kinases